Choujin Sentai Jetman, a Famicom game based on the TV tokusatsu series of the same name, has been fan-translated over into English as Bird Squadron Jetman by chronix.
The game is a platformer with a simple difficulty level and five playable characters, two of which use swords, two with guns, and one that uses fists. At the end of each stage, players combine their mechas into one giant robot to fight against the enlarged enemies in 1v1 versus combat.
Check out some screenshots below:
You can find the link to the translation patch here.
Choujin Sentai Jetman originally released on the Famicom.